Search1

Allen & Heath Qu-24 Digital Mixer

The Qu-24 features a J-shaped frame that dissipates heat and eases transport.

Allen & Heath’s Qu Series of digital mixers offer a perfect example of how digital mixing technology continues to get more powerful while becoming less expensive.

They combine total recall, comprehensive onboard I/O processing and effects, and moving faders with networking and USB connectivity. There are three mixers in the family—Qu-32, Qu-24 and Qu-16—each name indicating the number of mic inputs. For this review I tested the Qu-24.

The Qu-24 has a small footprint and an unusual J-shaped frame, which helps dissipate heat (it also made the desk easy to carry). A look around the back reveals balanced TRS line and XLR AnalogiQ microphone inputs (with 24-bit A/D) and balanced XLRs for all of the outputs (Main L/R, 10 Mix, four Matrix, and four Group). TRS jacks are provided for “Alt” and “2 Tk” outputs, as well as two stereo inputs. Also on the rear are USB, Ethernet and dSNAKE RemoteAudio ports (the latter using Cat-5 hardware). It’s clean, uncluttered and relatively easy to read in dim club lighting. A third 1/8-inch stereo input on the front panel provides a convenient means for connecting an iPod.

The work surface of the Qu-24 provides Mute, P/AFL, SEL(ect) and a motorized fader for each input channel. Toggling the faders to a second layer accesses the FX sends and returns, stereo inputs, group, matrix, and mix bus masters. A third custom fader layer will be discussed shortly.

Onboard processing is comprehensive and allowed me to leave the outboard rack home when doing local gigs. Each input has preamp gain, phase reverse, highpass filter, 4-band parametric EQ, compressor, gate, delay, pan and a switch that swaps the mic/line input with a USB return. Unlike most mixers in this price range, preamp gain can be applied to analog or USB inputs, and is controlled via rotary encoder—enabling gain settings to be stored and recalled along with scene data.

Inputs may be sourced individually or globally from “local” (mic/line), dSNAKE (remote mic/line via A&H AudioRack) or USB—the latter providing a choice of DAW playback via the rear panel USB port, or the desk’s “QuDrive,” an integrated multitrack recorder that supports 18 tracks (48 kHz/24-bit) simply by connecting a USB drive. Attaching a dSNAKE does not increase the maximum I/O count, but does allow you to mix and match stage with local (rear panel) connections.

Processing on every output includes a 31-band graphic EQ, compressor, 4-band parametric EQ, and delay for time alignment purposes. A&H has thoughtfully paired mix masters to a single fader where appropriate. For example Mixes 5/ 6, 7/ 8 and 9/ 10—clearly intended for ear mixes—are paired for stereo so their masters are controlled via one fader. Ditto for Groups 1/ 2 and 3/ 4, as well as Matrix 1/ 2 and 3/ 4.

Hit the Road Jack

I didn’t have much time to study the Qu-24 before using it for some local gigs, so I packed it in the trunk and went to work. Luckily for me it was a relatively simple gig with three inputs (two vocals and a guitar) and one monitor(!). After connecting the main outs to a pair of Electro-Voice ZLX-15Ps and Mix 1 out to a JBL EON15 monitor, I powered up the Qu-24. Ten seconds later a blank scene was loaded.

Assigning channels to a mix can be done at the touchscreen or by SELecting a mix, holding the Assign key, and SELecting channels to assign to that mix. I found the latter method faster because once you pick the mix and hold the Assign key you can quickly tap the SEL buttons on many channels. The process also allowed me to “poll” the channels that were assigned to the monitor mix, ensuring that the iPod used for walk-in music could not route to the monitor mix. This feature also enables channels to be removed from certain monitor mixes while remaining in others—as opposed to using a channel mute switch, which would kill the signal in all monitor mixes. It’s a subtle differentiation until you need it on deck like I did.

After setting input gains, I routed the channels to the monitor mix by pressing the “Mix 1” button—which swapped the faders to show send level to Mix 1—and raised the faders. Pressing the Fader Flip button enabled me to bring control of the GEQ to the faders to remove feedback, though you’ll have two pages because it’s a 31-band graph and there are 24 faders. Obviously, if you get the Qu-32 you don’t have to page the GEQ because there are enough faders to fit the entire ’graph.

SuperDuper

A&H’s SuperStrip maps a selected input or output to dedicated console controls. Illuminated buttons for highpass filter, PEQ, comp and gate in/out switches made it easy to see what’s in the audio path or not. Adjusting channel gain did not produce any zipper noise, nor was there a lag in the gain change. The low and high EQ bands are capable of shelf or peak/dip curves, but be aware that if you are using the SuperStrip to control EQ, you cannot scroll the bandwidth to shelf —you can only do so by tapping on the bandwidth control in the EQ screen and using the Screen Rotary. In any case, the EQ sweeps smoothly and was eminently useful without causing harm to the audio or any small furry creatures nearby. A few dB of boost at 4.25 kHz helped intelligibility of a male voice, while a dip in the area of 230 Hz took the boom out of the acoustic guitar.

I rely extensively on DCAs when mixing, so I was initially disappointed that the Qu-24 did not feature dedicated DCA faders (the Qu-32 does), but the console’s custom fader layer came to the rescue. The custom layer allows you to freely assign any I/O to any fader. For one gig I assigned eight drum channels to DCA 1, four guitar channels to DCA 2, keys to DCA 3 and vocals to DCA 4. I then created a custom layer with the DCAs on the first four faders, plus Stereo Return 1 (a CD player), two bass channels (mic and DI), five vocal channels and the main guitar channel to additional faders in that layer. This essentially enabled me to “premix” the drums, keys, guitars and vocals using the input layer, then use the custom layer to run the show. I was very happy.

The Qu-24 can store and recall a variety of data, such as complete scenes, as well as settings for PEQ, GEQ, gate, compressor and channel processing chains. These settings can be stored to and recalled from internal memory or a thumb drive via the front panel USB port. Along with all of the processing, the Qu-24 features four stereo FX processors capable of producing reverb, delay, ADT (automatic double tracking), chorus, flange, phase shift and gated reverb.

Effects are organized in a virtual rack with four slots and no limitations on effects type, so if you want four reverbs, you may have them. FX sends 1 through 4 will most likely be used to feed the rack but you have the option of feeding a single channel to an FX processor via direct out, or inserting the FX into an input or output channel—just in case you need to route an entire monitor mix through a flanger. All of the effects sound excellent. Hall 480 was my favorite for snare, with a decay time around 1.3 seconds, HF decay at 3.66 kHz and HF cut at 2.2.89 kHz. I kept returning to the 2Tap Delay for lead vocal and guitar solos, varying delay times between 200 to 320 ms, with a difference of 15 ms left-to-right to add a bit of space. Chorus and flange effects were very good, though I did wish for a pitch shift.

Besides its ability to stream 32 USB DAW sends and returns, the Qu-24 features A&H’s proprietary QuDrive, an onboard, 18-track USB recorder that requires nothing more than connection of a USB drive. Record and play functions are all accessible from the touchscreen, and if necessary, you could record via the DAW interface and QuDrive at once. A Seagate Expansion Portable Drive worked flawlessly (both solo and redundant to a DAW hookup), and the Qu-24 even provided the bus power.

iPad Control

A&H offers QuPad for controlling the Qu Series via iPad. QuPad looks beautiful, offering a big improvement over the console’s smallish screen. I’d want QuPad just for the visual feedback, even if I did not need the remote mixing capabilities because it adds features such as the ability to pinch bandwidth in the PEQ; A&H thoughtfully built a shelf into the desk surface to keep an iPad in place.

The Qu-24 operates at 48 kHz and, because it does not have provisions for external clocking, cannot run at other sample rates. For some users this may be a deal-breaker, but keep in mind that the Qu-24 is a live sound console first and foremost. Also keep in mind that at least one other very popular live digital desk operates only at 48 kHz (albeit with an external clock input capable of varying +/- 10 ppm) and adds a zero on the end of the price tag. Taken in context, I don’t feel it’s a big issue.

Solid Performer

Allen & Heath’s Qu-24 is an impressive package. You won’t need anything else to run a serious multi-zone P.A. system; it’s expandable and very affordable. Did I mention that it sounds excellent? All of the onboard processing is high quality, and it’s one of the few (if not only) mixers anywhere near the price that features recallable mic preamp gain. If you’re looking in this price range (or double), you need to check it out.

Steve La Cerra is a live sound and recording engineer based in New York.

CONS: No analog inserts. No DCA faders. No PC support for USB audio streaming. Operates only at 48 kHz.

Try This

The A&H Qu-24 allows direct connection of a USB drive to the front panel for recording up to 18 streams of audio. Format the drive by plugging it in and pressing Setup. On the touchscreen choose Utility > QuDrive. Press Format and then “yes” to the prompt. To record on this drive, press Home. On the touchscreen, select the QuDrive tab, then choose Stereo to record the L/R bus, or Multitrack to record channels 1 through 18. Press the Record button once to arm the tracks. Press the Play button to engage recording audio from each channel as an individual WAV file.